10 themes to watch in Formula E

Formula E's second season is a litmus test. Now is when the championship starts to prove its credentials as both a development hub for electric-vehicle technology and a legitimate, popular worldwide racing series.

But the ultimate challenge is facing the 10 Formula E teams: design and build new technology, get it working, get it optimised, and make sure you're not frying your batteries. Or at least a variation of those factors.

It's still the very beginning of a journey that will ultimately be defined by development of new technologies, but retains an old-school competition element as well.

That process takes a big step forward in China this weekend. The technologies have been opened up for season two, and there are some significant rule tweaks as well.

'OLD' VERSUS NEW

The all-electric championship broke new ground in motorsport across the 2014/15 campaign, but this was still very much an introductory phase. The chassis, the technical components - everything that made up the Spark SRT_01E - was the same for every team. Then it was just about which teams got to grips with the new technology best.

Each team was required to use the Spark SRT_01E last season, a Dallara-built car powered by a Williams battery, with McLaren-supplied electronics and a five-speed Hewland gearbox.

The cars look the same for this season, but opening up the regulations has meant the technical challenge underneath the bodywork outstrips even the arrival of Formula 1's turbo-hybrid era last year.

There are now eight different powertrains on the grid and a host of technical partners involved. Two teams are using the Spark specification from season one (Aguri and Andretti, but more on them later), while there is one customer arrangement (Dragon Racing will use Venturi's powertrain).

The other 'manufacturers' have opted for different powertrains that lie somewhere on the spectrum between Mahindra's conservative McLaren-Hewland adaption to the radical ideas adopted by Team China Racing and DS Virgin. Abt Audi Sport, e.dams Renault and Trulli complete the manufacturers.

Given that the season-one technology was still very new, making so many changes for the sequel is a bold move. But it is important for Formula E's roadmap, and that's why the decision has been made.

If any single technology runs away with the races this year, that will point to a major breakthrough in discovering the direction all-electric motorsport will take in the future.

EFFICIENCY IS THE KEY

A higher maximum race output combined with the available energy remaining the same - 28kWh - means efficiency becomes absolutely crucial in season two.

It's a no-brainer that the ideal scenario is to run at 170kW all the time, given that 150kW was a massive challenge last year. That difference equates to just under 30bhp, which is hardly insignificant.

While teams won't be able to harness all of that all of the time, naturally the goal is to run with as great a power output as possible. Especially when the difference between the season-one cap of 150kW and the new limit is so significant.

The law of averages also dictates that if a driver cannot save more energy than they did last season, but runs at the new higher power, then they'll have to slow down considerably more than they would have last season to make it to the end.

This is made even more relevant by the races being extended for season two. The change is small - only one or two laps - but it's more than enough at this stage to make it a significant variable when it comes to strategy.

The other factor in this equation is regenerated energy - some drivers are more adept at this than others, and since it's essentially free fuel it can make or break their chances.

But regenerated energy comes at a price: it increases heat in the battery. Which brings us neatly on to...

MANAGING THE BATTERY

While the Williams-produced battery remains the championship's control power source, it has been refreshed for season two.

Fundamental changes to the design weren't possible because the battery was homologated for two seasons. Not ideal for a battery originally designed to manage 133kW in a race (before a last-minute decision to raise peak power to 150kW in season one).

The cells within a battery all perform individually, which means in a poorly maintained pack some cells might be operating at 100 per cent capacity and others at a lower voltage. A battery's state of charge will reflect the highest individual cell, which means it could claim to be charging to 100 per cent when it is actually lower.

Williams has therefore replaced all the cells in every battery - in excess of 100 each time - to ensure as level a playing field as possible going into season two. It has also replaced some hardware components, such as wiring looms and electric boards.

The way teams used and maintained their batteries across the first season resulted in significant performance disparities by the end, and the eight differing technologies on the grid will only exacerbate that.

Teams are only able to employ one 'joker' replacement of the battery pack on each car (and each driver has two cars) over the course of the season.

THE DEVELOPMENT RACE

Formula E wants to establish itself as a hotbed for EV technology development. Eight 'different' powertrains on the grid is a start, but that will only be explored properly when the companies involved start to push the boundaries. And the knock-on effect of that is a performance boost for those who discover the best technologies.

In turn, those with bigger resources and better experience will come to the fore. Vincent Gaillardot, Renault's Formula E programme manager, believes the marques with a pedigree in world motorsport will have an advantage.

"You have to perform development and we'll benefit from that experience in F1," he tells Autosport.

"The manufacturers that have experience - Audi [in the World Endurance Championship], Citroen [world rallying], Renault - will have an advantage because they know how to manage a development programme."

This is why independent outfit Aguri did not want to take on the burden of developing its own solution in the shadow of the bigger marques. It's also why the likes of Mahindra opted for a more conservative 'new' solution - why give yourself more to learn, and more to hone, when you don't have the resources?

THE RADICALISTS

DS Virgin and Team China Racing have embraced Formula E's new era of development more than most, having adopted what each has admitted is a more "radical" solution than the others.

In the pursuit of greater torque and a smoother power curve, the Virgin DSV-01 and NEXTEV TCR001 have just one gear. This will eliminate the oscillations in power delivery caused by upshifts, while braking should be improved by the removal of the need to downshift. The latter in particular could be a particular benefit when it comes to bumpy, low-grip street tracks.

The other theoretical benefit comes from their respective systems having two motors instead of one. This should place less duress on the electric engine because they will be sharing the workload other teams are putting through one.

However, two motors come with a compromise: weight. The rear of the Formula E car is very heavy as it is, thanks to the battery, and thus its weight distribution is already significantly biased to the rear, so the teams hope they will be able to adjust their set-ups to negate the impact of a second motor.

Whether they can do that successfully will have a great impact on the package's competitiveness.

Maiden champion Piquet's squad battled reliability problems at Donington © LAT

One other limitation of the twin-motor philosophy is that the FIA does not allow torque vectoring in Formula E. This is the process of specifying how much power goes to each individual rear wheel, which would have offered a significant performance advantage if perfected.

The FIA avoids this by forcing each car to feed power from the motors through a differential, rather than directly to each rear wheel. That rids the radical solution of one of its greatest attributes.

The Virgin squad looked competitive in pre-season testing and was very quick in the first couple of sectors at Donington, where it is difficult to read too much into the times.

Check the sector-three efforts, and that's where Virgin trailed off. Given that it incorporates a chicane and two hairpins, the most representative part of the lap compared with the majority of the championship's venues, you could draw a negative conclusion.

China had reliability issues in the first test and ran at 150kW for most of the remaining four days, so its pace is even more of a mystery.

AND THE CONSERVATIVES

That conservative approach has its roots in electric racing being so new. There is no known 'right way' to do things because it hasn't been done before.

Tried and tested means very little in the Formula E paddock - most teams believe they hadn't extracted maximum performance out of the season-one powertrain, and now a number of outfits have gone in a different direction.

That said, some feel the original Spark SRT_01E still has more to give. Step forward Team Aguri and, belatedly, Andretti Autosport.

Aguri set its stall out early - ex-McLaren Formula 1 designer and Super Aguri F1 boss Mark Preston made it clear his team would continue with the season-one package to try and extract the most from that.

Andretti originally intended to run its own technology in season two, but a troubled on-track programme with the ATEC-01 left it with no timed laps after seven official days of testing. The pace showed by Robin Frijns on the one day it got with the Spark suggests the American outfit will be in the mix early on.

SO IS IT AUDI VERSUS RENAULT?

The Audi-backed Abt squad's pace over one lap in pre-season testing at Donington was ferocious. Record-breaking, actually, from both drivers. It is difficult to look past them as favourites.

Drivers Lucas di Grassi and Daniel Abt were keen to play down the significance of being quickest in testing but the car's long-run pace looked good as well. Either could very well line up on pole in Beijing.

Their nearest rival is probably going to be one of the e.dams Renault drivers. Sebastien Buemi, in particular, looked rapid in pre-season even though gearbox and battery gremlins hindered him and team-mate Nicolas Prost at times.

The one-lap pace wasn't as breakthraking as Abt's but it wasn't far off, as Buemi thought he never really got a clean lap at 200kW. So that battle should be fascinating.

Going back to the earlier point about development, and Abt/e.dams are well-placed thanks to their respective partners. As competition ramps up over the course of the season, there's no reason to think these two won't be leading the way.

That, based on season-one form, points to di Grassi and Buemi as the title favourites. Abt and Prost had impressive peaks but neither has the experience of their respective team-mates. Finishing the season stronger than they start is probably the likeliest outcome.

TENSER QUALIFYING

Formula E CEO Alejandro Agag had made introducing the superpole one of his main objectives for the 2015/16 season, and he got his wish.

An additional five-car, 15-minute shootout for pole, and the three points it brings, will be held at each round this season.

The drivers will be continue to be split into four groups of five, with the overall top five from across all the sessions going through to the superpole, which will take on a one-by-one, reverse-order format.

This will determine the top five starting positions on the grid, with sixth through to 20th set by the fastest times from the qualifying groups.

Naturally, that builds to a greater qualifying climax, but it should lead to tenser individual segments as well.

In order to cram the superpole into an already busy Saturday, the mini-sessions have had to be shortened to six minutes each. That gives drivers time for just one flying lap with 200kW of power - piling on the pressure.

WILL VILLENEUVE STICK AROUND?

One of the big additions to the 2015/16 Formula E season is undoubtedly 1997 Formula 1 world champion Jacques Villeneuve.

Even though the Canadian hasn't won a mainstream race since the 2008 European Le Mans Series round at Spa-Francorchamps, his return to a full-time single-seater programme is one of the main stories.

There was an IndyCar outing last year in the Indianapolis 500 amid a truncated World Rallycross programme. Before that, his career had been a mix of stockcar and sportscar outings since departing F1 midway through the 2006 season.

So, how has he looked? Solid. After ending the first test around a second off team-mate Stephane Sarrazin - who, let's not forget, won last season's London finale on the road - he was then quicker in the second test.

Villeneuve didn't get near his own personal best in the final test, spinning into the gravel in an afternoon session disrupted by rain, but the early indications are quite positive. Though of course, that was all at a track where he was running for six days.

So will he complete a full season for the first time since 2005? How he fares at getting to grips with street circuits with minimal running will be the main factor when it comes to getting an answer.

A DIFFERENT KIND OF FANBOOST

Fans being able to vote for their favourite drivers to receive a power boost is one of Formula E's more controversial regulations, but it exists nonetheless - and is changing for this season.

Last year that hike came in the form of a five-second boost to 180kW of power, up from the maximum race output of 150kW.

Now a revised power hike will be awarded to three drivers once voting has closed six minutes into the race - which means in-race voting.

Because the peak race power goes up to 170kW for the second season, Fanboost recipients will now get an additional 100kJ of energy, to be used in a power window between 180kW and 200kW. That boost, which remains applicable only in one go, will now only be available after drivers swap cars mid-race.

You can also vote now using hashtags on social medial platforms Facebook, Twitter and Instagram.

This week's edition of Autosport magazine features a full Formula E 2015/16 preview, including Sebastien Buemi on the venues, and a team-by-team guide.